Bladder cancer is a prevalent malignancy in the United States. In 2010, approximately 70,000 newly diagnosed cases of bladder cancer are expected; of those, more than 14,000 are expected to die. According to the American Cancer Society, the five-year survival rate for patients diagnosed with bladder cancer is 98% at stage 0, 88% at stage I, 63% at stage II, 46% at stage III, and 15% at stage IV. These bleak statistics highlight the fact that early detection of bladder cancer is critical for the intervention of the disease. The estimated overall cost per patient from diagnosis of bladder cancer to death is about US $96,000-$187,000; and the total cost amounts to US $3.7 billions.
Early detection of bladder cancer is essential for removing the tumor with preservation of the bladder, avoiding local complications from the tumor such as bleeding or infections, avoiding metastasis and hence improving prognosis and long-term survival. In bladder cancer, ˜90% are transitional cell carcinomas, ˜5% are squamous cell carcinomas, and ˜2% are adenocarcinomas. Of the transitional cell carcinomas, ˜75% present as superficial tumors; of which ˜50-70% will recur and ˜10-20% will progress to invasive bladder tumors. Patients are therefore kept under surveillance for early detection of recurrences.
The current standard methods to detect bladder cancer include cystoscopy and urine cytology. Cystoscopy involves inserting a thin, lighted scope through the patient's urethra into the bladder. It is invasive, unpleasant, and expensive, which in turn leads to poor patient compliance. In addition, cystoscopy often yields false-positive results. Urine cytology is an alternative procedure that involves checking the number and appearance of cells in a urine sample. It has a low sensitivity for detecting small or low-grade bladder tumors.
Numerous urine-based markers have been tested for bladder cancer detection and surveillance. These markers include complement factor H (BTA-Stat/TRAK), nuclear matrix proteins (NMP22), mucin-like antigens, hyaluronic acid, hyaluronidase, survivin, soluble Fas, telomerase and detection of chromosomal aneuploidy and deletion using fluorescence in situ hybridization (UroVysion®). However, none have acceptable sensitivity and specificity as a routine tool for bladder cancer diagnostics and surveillance.
Accordingly, there remains a continuing need for a urine-based test with adequate sensitivity and specificity in the detection and diagnosis of bladder cancer in humans. It would be advantageous to develop a non-invasive and reliable screening method that encourages initial and follow-up screening. The present invention cures all the prior art deficiencies and provides a novel method of detecting DEK protein in urine. The present method provides a high sensitivity and specificity of 79% and 83%, respectively, and can be used as a diagnostic tool to detect bladder cancer in humans.